Improvement in combined governors, steam-valves, and cut-offs



` -A JOHNSTON. `(.mbin'ed Governors, Steam-Valves, a'ndCut-fs.'

Patented July 7, 874,

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. Iwan/Effi TH GRAPHIC B0. PNITYQLTHJBS: 4-l PARKPLACE, NX.

UNITED STATES PATENT CEEIGE.

ALLEN JOHNSTON, OF OTTUMVA, IOWA.

IMPROVEMENT IN COMBINED GOVERNORS, STEAM-VALVES. AND CUT-OFFS.

Specication forming part of Letters Patent No 152,750, dated July 7, 1874; ilpplicatOIl led May 16, 187

To all whom it may concern:

Be it known that I, ALLEN JOHNSTON, of Ottumwa, Vapello county, Iowa, have invented certain new and useful Improvements in Combined Governor, Steam-Valve, and

lut-Off for Steam-Engines, of which the following isa speciiieation:

This invention, which relates to rotary val ves, has for its object to maintain inthe steam-cylinder full and uniform boiler-pressure, so long as the port in the chest leading to the cylinder is open, and to regulate the power by cutting ofi" steam earlier or later in the stroke according to circumstances, the balance of the stroke being eiected by expansion of the steam. To this end I combine with the rotary valve a cutoff which, while carried by and rotating with said valve, is, at the same time, connected with and operated by the governor to move independently of the valve, so as to decrease or increase, according to the speed of the engine, the length ot' the steam opening or slot in the va-lve, through which steam passes into the cylinder-ports.

The principal advantages of this arrangement are, rst, that the steam-ports are at all times of the same size, so that as long as they' are unclosed by the valve there is full and uniform boilerpressure in the cylinder; and, sccondly, that the exhaust is left more free and unobstructed than it would be were the cutoii' combined not with the rotary valve, but with the steam-ports ofthe cylinder.

The nature of my invention, and the manner in which* the same is or may be carried `into eii'ect, will be understood by reference to the accompanying drawings, in which- Figure l is a vertical central section of a valve and regulating mechanism constructed and organized in accordance with 1nyinve11- tion. Fig. 2 is a perspective view ofthe valve and its stem, detached. Fig. 3 is a view-ot' the under side of the valve. Fig. 4 is a view of the valve-seat and steam and exhaust ports. Fig. 5 is a view ofthe cut-oft', detached. Fig. 6 is a horizontal section through the hollow stem or sleeve to which the governor-balls are attached in the plane of the racks, by which the cut-oft' is operated.

The steam-chest is represented, at A, with steam-supply pipe B leading into the chest from the boiler. C is the valve, having a tubu- Y lar stem, D, tting snugly in and passing up through a supporting-sleeve, D, which projects upward from the top ofthe steam-chest. This sleeve D is prolonged by a rotary sleeve, E, which is grooved to receive a spline, a., on the valve-stem, and is also keyed or fastened to said stein by one or more screws or pins, b. The external sleeve E is rotated by suitable means, consisting, in this instance, of a beveled gear-wheel, E1, iiXed on it and meshing with a like wheel, E2, to which motion is imparted from the engine. ThereA should be a packing between D and E, as seen Ain lFig. l. The rotary movement of sleeve E causes a corresponding rotation of the valve. "The valve C is formed with a steam-opening, c, extending entirely through it, and of the length nearly of a semicircle. The remaining half of the valveis occupied b T an exhaust-space, d., formed on the under side of face of the valve. The valve-seat F is formed with the central eX- haust-port c and the two steam-ports j', one on each side of the exhaust, and diametrically opposite one another. On top ofthe valve is the cut-oit, consisting of a sectoral plate, G, provided with a vertical cut-off face, g, which fits in the steam-opening c and extends down therein so as to be iinsh at its lower end with the under face of the valve. The sectoral plate is provided with a hub, h, encircling and f1tting the valve-stem, on which, as its axis, the said plate can turn. VBy moving the cut-off sector toward or away from the end of the steam-opening opposite to that against which the face g normally stands, the length ot' said steam opening can be correspondingly decreased or increased. The cuto'is connected with the governor by mea-ns of a spindle, H, iitting and supported within the tubular valvestem D, and attached to the hub of the sectoral plate by means of a pin or screw, i, inserted through the hub into the spindle, and passing through a horizontal slot and intermediate sleeve D ofsuch length as will permit the necessary independent movement ofthe cut-oit'. The cut-off spindle, at its upper end, is prowided with a pinion, j, into which mesh two rack-bars, k, one on each side of the pinion, jointed, by connecting-rods, to arms or levers I, carrying the regulator-balls, and pivoted to the rotary sleeve E, as seen in Fig. 1. To regu'- late the resistance to be offered to the spreading apart of the ball-levers, a governingspring, J, may be attached to the top of sleeve E, as seen in Fig. l, so as to bear at its ends on the two levers, its tension being regulated by means of a tightening nut or bolt, K.

Under the arrangement above described it will be noted that, while the cut-off rotates with the valve, it will independently of the latter be operated by the governor to more or less shorten the steam-opening according as the governor-balls are more or less spread apart.

The general operation of the valve in admitting and exhaust-ing steam will be understood without further explanation.

By means of the combination described I obtain full boiler-pressure on the cylinder-piston all the time the steam-port is open, this pressure, so long as the port remains open, being always uniform, whatever may be the speed; and the power applied is regulated by a greater or less expansion of steam in the cylinder, this depending upon the cut-off. The screwing down of the regulating-spring will increase the power or speed by holding the governonballs down, and thus leaving the ports open for a longer time. I would observe,

however, that the spring is not absolutelyT essential, and may be dispensed with, if desired. It will be also seen that the exhaust is left free and unobstructed under all conditions.

Having now described my invention, and

the manner n which the same is or may be carried into effect, what I claim, and desire to secure by Letters Patent, is-

1. rllhe combination, in a steam-valve, of thc following elements, namely: A rotary valvedislr having a steam opening extending through it, and an exhaust-space on its under face 5 a valve-seat, with steam and exhaust ports against which the face of said valve bears, the steam-ports being shorter than the steam-opening in the valve; and a cut-off rotating with said valve, but connected with and operated by the governor, independently of the valve, substantially as shown and set forth.

2. The combination, with the rotary valve and valve-stem, of the cut-oftl and cut-off spindle, carried by and rotating with said valve, and racks connected with and operated by the governorball levers, substantially as and for the purposes described.

5. In combination with the cut-off, rotating with the valve, and the governor mechanism, connected with and operating said cutoff independently of said valve to regulate the lengt-h of steam-opening in the same, the regulating spring or springs, applied to the governorball levers7 substantially as and for the pur poses shown and set forth.

In testimony whereof I have hereunto signed my name this 12th day of May, A. D. 1874.

ALLEN JOHNSTON.

Witnesses A. G. Hnnnow, J. T. HAGKWORTH. 

